SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e24419b4ea81d14c8355fa2777594b2e5db9461e6c751e514f1101dfe87b8172' 
  AND token = 'wRksYXGLCi/EUb7NxAsRgs3aOeaHUibhcDvYQmJDC5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}